The present invention pertains generally to devices which are useful in ophthalmic laser surgery. More particularly, the present invention pertains to contact lenses which will stabilize the eye of a patient during ophthalmic surgery. The present invention is particularly, but not exclusively, useful as a contact lens which stabilizes the eye and also aspirates the gas and debris that is created as stromal tissue is photodisrupted during intrastroma ophthalmic laser surgery.
During laser surgery, the interaction of the laser beam with body tissue involves a phenomenon which is generally referred to as photodisruption. The result of photodisruption on the affected tissue is really three-fold. In part, the tissue is vaporized. In part, there are mechanical effects on the tissue which become manifest in the tearing, separation and division of the affected tissue. Finally, there may be thermal effects which include charring and scorching of the affected tissue. The consequences are mixed. Along with the beneficial and intended consequences for a particular surgical procedure (i.e. the cutting or removing of tissue) there are also unwanted consequences of photodisruption. These unwanted consequences typically result from the generation of gas and tissue debris which have the potential to disrupt the surgical procedure. Preferably, the unwanted gas and debris can be removed from the surgical site.
For laser surgical procedures which are accomplished on external or exposed tissue, the problem of removing gas and debris from the surgical site is relatively easily solved. In this case, the gas will dissipate and the debris can be easily washed away or aspirated. The case is quite different, however, where internal tissue is involved. Specifically, in the case of intrastromal procedures wherein a specific volume of internal stromal tissue is to be photodisrupted, there is a real concern about how to best remove the unwanted gas and debris. Clearly, this gas and debris needs to be removed for several reasons. These reasons include: 1) the need to reduce the unwanted build up of gas pressure in the stroma during a surgical procedure; and, 2) the need to remove debris particles and obstructions which could otherwise interfere with the laser beam during subsequent photodisruption of additional stromal tissue. In order to address these needs, reliance on something more than the body""s own ability to resorb the affected tissue is necessary.
In light of the above, it is an object of the present invention to provide a device which will effectively reduce the unwanted build up of gas pressure in the stroma during ophthalmic laser surgery. Another object of the present invention is to provide a device which will effectively remove debris particles and obstructions from the stroma which could otherwise interfere with the subsequent photodisruption of additional tissue. Yet another object of the present invention is to provide a device for removing the gas and debris that results during the photodisruption of stromal tissue which is easy to use, relatively simple to manufacture, and comparatively cost effective.
A device for removing gas and debris from the stroma of an eye during intrastromal ophthalmic laser surgery includes a contact lens and a suction apparatus which is interconnected with the contact lens. Further, the contact lens is formed with a recessed chamber, and the suction apparatus is connected in fluid communication with the recessed chamber. With this combination, when the recessed chamber of the contact lens is positioned over the eye, and the suction apparatus is activated, the cornea of the eye is drawn into the recessed chamber to hold the cornea against the contact lens. This action also stabilizes the eye during subsequent laser surgery.
Once the cornea of the eye has been stabilized by the contact lens, a laser source can be activated to generate a laser beam. For purposes of the present invention, this laser beam will be directed through the contact lens to perform the desired intrastromal ophthalmic laser surgery. When doing so, stromal tissue is photodisrupted by the laser beam in a predetermined manner. It is well known, however, that as stromal tissue is photodisrupted by a laser beam, gas and debris are formed as by-products in the stroma. To compensate for this result, and avoid the unwanted consequences which can ensue if nothing is done, the gas and debris need to be removed as quickly 10 as possible. In accordance with the present invention, the removal of gas and debris from inside the stroma can be accomplished by aspiration in either of two ways. For both of these ways, a fluid communication channel into the stroma needs to be created.
With one embodiment of the present invention for removing gas and debris from the stroma during intrastromal ophthalmic laser surgery, the laser system itself is used to create an external opening into the stroma. Importantly, in addition to establishing a fluid communication channel with the interior of the stroma, this external opening needs to remain in fluid communication with the recessed chamber during the surgical procedure. Stated in the negative, the external opening into the stroma can not be created wherever there is a contact between the cornea and the contact lens that would obstruct the external opening. Then, with the opening undisturbed, subsequent activation of the laser system can be accomplished in a manner which will place the gas and debris that results from the photodisruption of tissue in fluid communication with the external opening. The external opening, of course, will also be in fluid communication with the recessed chamber, and the recessed chamber will be in fluid communication with the suction apparatus. Accordingly, the suction apparatus can aspirate the gas and debris from the stroma and thereby remove this material from the eye.
With another embodiment of the present invention for removing gas and debris from the stroma during intrastromal ophthalmic laser surgery, a hollow probe is mounted on the contact lens to extend into the recessed chamber. Thus, for this embodiment of the present invention, the suction apparatus is connected in fluid communication with the recessed chamber through the probe. With this configuration, when the recessed chamber of the contact lens is positioned over the cornea, and the suction device is activated to draw the cornea into the recessed chamber, the probe will penetrate into the stroma. Subsequent activation of the laser system will then need to begin at the tip of the probe and continue from there through the stroma as desired. In this manner, the tip of the probe will remain in fluid communication with the stromal tissue that is being photodisrupted so that the resultant gas and debris can be removed from the eye.